* {
    margin: 0;
    padding: 0;
}

li,
a {
    list-style: none;
    font-size: 18px;
    text-decoration: none;
    color: #fff;
}

.aaa {
    display: block;
    width: 200px;
    height: 50px;
    text-align: center;
    line-height: 50px;
    background-color: rgb(10, 14, 14);
    border: 1px solid #000;

}

#box {
    width: 100px;
    height: 100px;
    background-color: aqua;
    position: absolute;
    left: 0;
    top: 0;
}